Long Neck Birds as Upward Flow and Loop-Back Symbols
Image C is Pictish, and I like it because it has a horizontal plane outflow from the mouth (of a head-torus symbol), and the bird neck goes above the barrier and then does a loop-back curl. The horse neck is also doing a horizontal plane outflow (from the body-torus of the horse), and it's head direction then shows a downward flow.
Image D is labelled Greek/Mycenaean and uses horse necks instead of birds for the bilateral loop-backs. On April 8th, a few days ago, I posted similarly with Mooses and more horses. https://www.facebook.com/share/p/1CJb8rD74P/
On image D, the upside-down double-Axe is an upward flow symbol, just like an upside-down Mace. https://ca.pinterest.com/stevenbhalls/mace/ https://ca.pinterest.com/stevenbhalls/axe/
The Axes are more difficult to decode but often they are used in the pattern where one side is upward, the opposite side is downward flow. Combining a spearhead with an Axe blade nearby gives a bidirectional symbol.
I didn't intend to post about Axes, but it rarely gets a teaching opportunity, so I used this post. Birds are too easy.